When handling equipment which is submersed in liquid, for instance a submersible pump, it is a normal practice to have a chain attached to the equipment. An end of the chain is held above the liquid level, and when the equipment has to be lifted (and subsequently lowered), a lifting hoist is attached to the out-of-liquid end of the chain. This procedure requires a somewhat laborious engagement of a hoist hook with a shackle, and the latter with a lifting bail, or handle, on the equipment. As this operation is troublesome and time consuming, another procedure has become common. In this, a hoisting hook has its safety lock disabled, and the hook is angled to find and engage the equipment, by snaring the lifting bail thereof for instance. This introduces a considerable safety risk to the personnel as, clearly, the equipment load may loosen from the un-safetied hook, especially with any oscillation or swinging of the hook suspended load.
Another problem, which is especially important in sewage pump stations, is that the original lifting chain of the pump unit corrodes at the liquid level and, therefore, must be replaced at recurring intervals.
One way to overcome these difficulties is to arrange a guide unit from above, i.e., from ground level, down to the submersed load, and permanently attached to the submersed load. A lifting device, then, is guided along the guide unit, and down to the submersed equipment, when the equipment must be raised to ground level. The guide unit, then, must be made of a material that does not corrode, e.g., nylon for instance, and be so thin or filamentary, that it would not be mistaken for a load-lifting agent.
An example of a lifting device which operates according to the aforesaid is shown in the Swedish Patent No. 810 2854-0. In this, a lifting eye is lowered down to a submersible pump along a guide cord, and is hooked to a short chain attached to the pump. This device has good functioning for moderate weight loads, but does not meet the requirements for heavy loads where the connection between the lifting device and the pump must be more solid.
In light of the foregoing, it is an object of this invention to set forth a means for, and a method of, handling a submersible equipment, comprising a lifting device of the type that is described in the Swedish Patent No. 900 1774-0. This lifting device includes a shackle which can be turned relative to the body of the lifting device. Too, the body is provided with a lock, acted upon by the shackle, which prevents a turning of the lifting hook during lifting and/or loading, and is so designed that an unloaded lifting hook takes an evacuating, open position.